The long-term goal of this project is to create an efficient, unique, and versatile laser instrument that will have applications in a large range of surgical procedures including dermatology, laryngology, otology, and ophthalmology. In the near-term, these instruments will act as efficient replacements for Er:YAG and Er:YSGG lasers used in several dermatological applications. The two major specific aims for Phase I are: (1) Demonstration of a compact fiber laser instrument emitting at an ideal wavelength and with continuously adjustable pulse duration and highly controlled repetition rates for precision micro- fractional skin resurfacing applications. The research design and methods for this aim include: o Construction of a compact and efficient laser-diode-pumped an Er:ZBLAN (2.8 5m) fiber laser with continuously variable pulse durations (10 5s - 100 ms) o Demonstration of appropriately high pulse energies from an ultracompact high efficiency laser system (>10 mJ pulse energies in 100 5s pulses, and up to 500 mJ pulse energies for 100 ms pulses) o Demonstration of a beam quality that can be focused to controlled micro-spot sizes with dimensions between 10 5m and 100 5m (2) Performance of skin resurfacing studies at the Beckman Laser Institute (Univ. of Calif., Irvine) using the above-described instrument, to simulate the effects that are observed with an Er:YAG laser, and operating over a broad range of pulse durations, pulse burst sequences and pulse repetition rates with a goal of uncovering novel clinically-beneficial operating regimes. The research design and methods for this aim include: . Demonstration of ex-vivo skin ablation under a broad range of laser parameters o Use of histology to quantify ablation and thermal damage to determine equivalency with FDA approved Er:YAG. Investigation of the effect of fluence, pulse length and multiple pulse irradiations. In Phase II, we will: (1) Develop scanning system and improve beam delivery. (2) Develop an advanced prototype of our fiber laser instrument. (3) Conduct in vivo and clinical studies and demonstrate clinically superior skin resurfacing effects. PUBLIC HEALTH RELEVANCE: The primary relevance of this research is that it will lead in the long term to efficient, unique, and versatile laser surgical instruments that will have applications in a large range of surgical procedures including dermatology, laryngology, otology, and ophthalmology. In the near-term, these laser surgical instruments will act as efficient replacements for Er:YAG and Er:YSGG lasers used for several dermatological applications. A key advantage is that the proposed instrument will enable more effective and lower cost procedures, and enable quicker healing from the surgery.